The present invention relates generally to computer systems, and more particularly to data input techniques for computer systems.
Computers are becoming increasingly powerful, lightweight, and portable. The computing power of computers that once filled entire rooms is now residing on a desktop. Laptop, notebook, and sub-notebook computers are virtually as powerful as their desktop counterparts. Even smaller hand-held computers are now capable of computing tasks that required much larger machines a few short years ago.
As a part of this trend, computerized personal organizers are becoming increasingly popular with a large segment of the population. Computerized personal organizers tend to be small, lightweight, and relatively inexpensive, and can perform such functions as keeping a calendar, an address book, a to-do list, etc. While many of these functions can also be provided in conventional computer systems, personal organizers are very well suited to the personal organization task due to their small size and portability. Personal organizers are available from many companies including Sharp and Casio of Japan.
A relatively new form of computer, the pen-based computer system, holds forth the promise of a marriage of the power of a general purpose computer with the functionality and small size of a personal organizer. An example of a pen-based computer system is the Newton.RTM. 120 pen-based computer made and marketed by Apple Computer, Inc. of Cupertino, Calif.
A pen-based computer system is typically a small, hand-held computer where the primary method for inputting data includes a "pen" or stylus. A pen-based computer system is commonly housed in a generally rectangular enclosure, and is provided with a dual-function display assembly that can serve as both an input device and an output device. When operating as an input device or "tablet", the display assembly senses the position of the tip of a stylus on the viewing screen and provides this positional information to the computer's central processing unit (CPU). Some display assemblies can also sense the pressure of the stylus on the screen to provide further information to the CPU. When operating as an output device, the display assembly presents computer-generated images on the screen.
The dual-function display assemblies of pen-based computer systems permit users to operate the computer as a computerized notepad, among other functions. For example, graphical images can be input into the pen-based computer by merely moving the stylus on the surface of the screen. As the CPU senses the position and movement of the stylus, it generates a corresponding image on the screen to create the illusion that the stylus is drawing the image directly upon the screen, i.e. that the stylus is "inking" an image on the screen. By "ink" it is meant that pixels on the screen are activated in such a manner that it appears that the stylus is leaving a trail of ink on the display assembly. With suitable recognition software, the "ink" can be recognized to input text, numerics, graphics, and other recognized information into the pen-based system.
Computer systems require user input for one reason or another. The typical input sources are a keyboard, a mouse and a track ball, and in the case of pen-based computers, a stylus. One conventional way of reducing the burden on the user to individually enter or "ink" each character is to provide a list to the user whereby the user need only select one of the list items to thereby cause the data to be entered. These lists are generally arranged in a alphabetical order. Although such lists alleviate the user from having to type in or otherwise enter the data, the data entry process is still burdensome on the user. Namely, if there is a list available, which in many cases there is not, the list is generally too long and requires a substantial amount of time for the user to identify the item to be selected. Also, if the user has waded through the list and not found the desired data, the user becomes frustrated due to the wasted time and effort. Therefore, there is a need for an improved user interface that allows a user to enter data with a greater ease of use.